Investigation of mechanical, microscopic, and leaching properties of coal-based solid waste geopolymer mortar activated by soda residue and phosphogypsum.

In this study, coal-based solid waste geopolymer mortar (SWCB) was prepared by using granulated ground blast-furnace slag (GGBS) and coal gasification coarse slag (CGCS) as precursors, and soda residue (SR) and phosphogypsum (PG) as activators, with gangue sand (GS) utilized as an inert filler. The corresponding compressive strength, fluidity, ion leaching, and microstructure of the developed SWCB were systematically investigated under varying solid contents, binder-to-sand ratios, and activator ratios. The findings suggest that the incorporation of activators promoted the dissolution of the silicon-aluminum phase in GGBS and CGCS into Al(OH)4-, [SiO(OH)3]-, and [SiO2(OH)2]2-, which could subsequently react with the Ca2+ and SO42- released by PG, forming AFt and C-(A)-S-H, thereby playing a crucial role in enhancing matrix strength. AFt was the predominant hydration product in the early reaction stage. The morphology of the AFt phase evolved from needle-like or filamentous to fine and coarse rods as hydration progressed. Initially, the formation of C-(A)-S-H gel increased with rising activator content before decreasing. The optimal synergy between AFt and C-(A)-S-H was observed at an activator content of 30 %. However, the growth of gypsum crystals was hindered when the activator content surpassed 30 %, resulting in a plate-like or columnar morphology. C-(A)-S-H gel exhibited remarkable adsorption capability towards P atoms attributed to intermolecular Van der Waal's forces, enabling simultaneous physical encapsulation of P atoms, while Cl element immobilization was primarily attributed to the contribution of SiOH sites to Cl adsorption.

Impact of foot progression angle on spatiotemporal and plantar loading pattern in intoeing children during gait.

Intoeing in children is a common parental concern, but our understanding of the impact of foot progression angle (FPA) in these children leaves remains limited. This study examines the relationship between FPA and plantar loading pattern, as well as gait symmetry in children with intoeing. The sample included 30 children with intoeing caused by internal tibial torsion, uniformly divided into three groups: unilateral intoeing, bilateral mild intoeing, and bilateral mild-moderate intoeing. The relationship between FPA and plantar loading pattern, and gait symmetry within and among groups were assessed using dynamic pedobarographic and spatiotemporal data. Results indicated a significant correlation between FPA and peak pressure, maximum force, and plantar impulse in the medial and central forefoot, and also the medial and lateral heel zones for both bilateral intoeing groups. Significant differences were observed only in subdivided stance phase, including loading response, single support, and pre-swing phases, between the unilateral intoeing and bilateral mild intoeing groups. These findings suggest that FPA significantly affects the forefoot and heel zones, potentially increasing the load on the support structures and leading to transverse arch deformation. While children with intoeing demonstrate a dynamic self-adjustment capability to maintain gait symmetry, this ability begins to falter as intoeing becomes more pronounced.

Risk factors for femoral overgrowth after femoral shortening osteotomy in children with developmental dysplasia of the hip.

Objective: Developmental dysplasia of the hip (DDH) refers to a series of deformity of acetabulum and proximal femur and abnormal relationship between them, it represents the most common hip disease in children. Overgrowth and limb length discrepancy (LLD) was common complication in children undergoing femoral shortening osteotomy. Therefore, the purpose of this study was to explore the risk factors of overgrowth after femoral shortening osteotomy in children with DDH. Methods: We included 52 children with unilateral DDH who underwent pelvic osteotomy combined with femoral shortening osteotomy between January 2016 and April 2018, including seven males (six left and one right hip) and 45 females (33 left and 12 right hips) with an average age of 5.00 ± 2.48 years, and an average follow-up time of 45.85 ± 6.22 months. The amount of overgrowth and limb length discrepancies (LLDs) were calculated. The risk factors of femoral overgrowth ≥1 cm and LLD ≥ 1 cm were analyzed. Results: There were statistical differences in age (p < 0.001) and operation duration (p = 0.010) between the two groups with femoral overgrowth <1 cm and ≥1 cm. There was a statistical difference in operation duration (p < 0.001) between the two groups. Age (p < 0.001) was an independent influencing factor of femoral overgrowth in children with unilateral DDH after pelvic osteotomy and femoral shortening osteotomy, and a risk factor (p = 0.008) of LLD in these children. Conclusion: The overgrowth and LLD of children with developmental dislocation of hip after pelvic osteotomy and femoral shortening osteotomy are significantly related to age. There was no significant difference between different pelvic osteotomies for femoral overgrowth in children. Therefore, surgeons should consider the possibility of LLD after femoral shortening osteotomy in children of a young age.

Application of three-dimensional printed navigation templates to correct lower limb deformities in children by the guided growth technique.

Objective: Currently, individualized navigation templates are rarely applied in pediatric orthopedic surgery. This study aimed to explore the potential of navigation templates obtained using computer-aided design and three-dimensional (3D) printing to correct lower limb deformities in children by the guided growth technique. Methods: We prospectively studied 45 children with leg length discrepancy (LLD) or lower limb angular deformities, who underwent guided growth surgery involving 8-plate. In total, 21 and 24 children were included in the navigation template (group A) group and in the traditional surgery (group B) group, respectively. Mimics software was used for designing and printing navigation templates. The operation time, X-ray radiation exposure, damage to cartilage, and postoperative complications were recorded. Results: The mean operation time in groups A and B were 20.78 and 28.39 min, respectively, and the difference was statistically significant. Compared with group B, the intraoperative exposure of X-rays in group A was reduced by 25% on average. After 9-24 months of follow-up, the deformities were corrected in both groups. No significant differences in the treatment effect were noted between the groups, and no complications occurred. Conclusions: Using the individualized navigation template in the guided growth technique made the surgical procedure convenient and simple to perform. In addition, the operation time and intraoperative exposure to X-rays were reduced. We consider that 3D printed navigation templates can facilitate the accurate completion of corrective surgeries for lower limb deformities in children, which is worthy of promotion and application.

Anteroposterior pelvic radiograph is not sufficient to confirm hip reduction after conservative treatment of developmental dysplasia of the hip.

The purpose of this study was to investigate whether an anteroposterior pelvic radiograph alone is sufficient to confirm hip reduction after conservative treatment or whether MRI could be alternatively performed. A total of 133 children (145 hips) were enrolled. All children were examined by anteroposterior pelvic radiographs and MRI. Three experts interpreted anteroposterior pelvic radiographs and then verified these results on MRI. For patients with inconsistent results between anteroposterior pelvic radiographs and MRI, the continuity of Shenton's line and Calve's line was recorded, and the medial clear space of bilateral hips was measured for unilateral cases. There was complete agreement between the three experts in the interpretation of anteroposterior pelvic radiographs of 111 (76.55%) hips; there was disagreement in the remaining 34 hips, with two experts diagnosing satisfactory reduction in 13 hips and dislocation in 21 hips. Assuming that the judgment of two or more doctors on anteroposterior pelvic radiographs was taken as the final result, 17 hips (11.72%) were misjudged. There was no statistically significant difference between the actual in-position group and the actual dislocation group in terms of the continuity of Shenton's line ( P = 0.62) and Calve's line ( P = 0.10) and the medial clear space of bilateral hips ( P = 0.08). In children less than 1 year of age with developmental dysplasia of the hip treated conservatively, the use of anteroposterior pelvic radiographs alone to judge hip reduction might result in misdiagnosis and missed diagnosis. MRI could be alternatively used to detect hip reduction after conservative treatment, especially when the doctor was not familiar with ultrasound in the presence of plaster.

The Effect of Tibial Insertion Site in Single-Bundle ACL Reconstruction during Gait Based on Motion Capture and Musculoskeletal Model.

The purpose of this study was to investigate the effect of tibial insertion site (TIS) of the anterior cruciate ligament (ACL) in single-bundle ACL reconstruction on ligament force during gait. A musculoskeletal model with an ACL ligament was created, and gait data were collected based on the motion capture system from seven female patients with single-bundle ACL reconstruction. The TIS was simulated in OpenSim and systematically changed in 2.5 mm intervals (2.5 mm, 5.0 mm, and 7.5 mm) in the anteroposterior and mediolateral directions from the center. The changes of the ACL force overtime and peak force were compared using the Pearson correlation and paired t-test separately for all simulated TISs. The results indicated that anterior movement of the TIS would significantly increase the loading of reconstructed ACL and the risk of secondary injury, but the posterior TIS would keep the ACL loose during gait. The mediolateral change of the TIS also affected the ligament force during gait, which increased in the medial direction and decreased in lateral direction, but the magnitude of the change is relatively small compared with those measured in the anteroposterior direction. Therefore, during preoperative surgery planning, defining the outline of the ACL attachment site during surgery can help to guide the decision for the TIS and can significantly affect the reconstructed ACL force during gait, especially if the TIS is moved in the anteroposterior direction.

Effects of orthotic insole on gait patterns in children with mild leg length discrepancy.

BACKGROUND: Leg length discrepancy (LLD) is commonly associated with compensatory gait strategies leading to musculoskeletal disorders of the lower extremity and lumbar spine. Orthotic insole (OI) is considered as a conservative treatment for patients with mild LLD, especially for children. However, the restoration of normal gait when wearing OI with foot lift are still poorly understood. RESEARCH QUESTION: What are the immediate effects of OI on the gait patterns in children with mild LLD? METHODS: Gait data and plantar pressure data were collected for 12 children with mild anatomical LLD in barefoot and OI conditions. Paired t-test was performed to determine the changes in gait between these two conditions, and also the symmetry between limbs in the same condition for spatiotemporal, kinematic, and kinetic variables. RESULTS: Children with mild LLD showed an immediate gait improvement confirmed by increased step length and velocity, decreased peak plantar pressure in both limbs with OI. Additionally, the significant between-limb differences disappeared for peak ankle dorsiflexion, hip adduction, pelvis upward obliquity and also second peak plantar pressure with OI, which improved gait symmetry. SIGNIFICANCE: This study provides a better understanding of the immediate effect of OI with foot lift on biomechanical changes in gait, which identify that OI with foot lift could be a potential therapeutic option for children with mild structural LLD to improve gait metrics.

Four-Subtest Index-based Short Form of WAIS-IV: Psychometric Properties and Clinical Utility.

Short form of the Wechsler Adult Intelligence Scale is often needed to quickly estimate intelligence for time-saving or screening in clinical practice. The present study aims to examine the psychometric properties of Chinese version of the four-subtest index-based short form (SF4) of WAIS-IV (FS) and to confirm its clinical application. 1,757 adults from the WAIS-IV Chinese version standardization sample and 239 mixed clinical samples including patients with schizophrenia or schizoaffective disorder (SCH), obsessive-compulsive disorder (OCD), and mild or moderate intellectual disability (ID) were used. Demographic data were collected and intelligence was assessed with WAIS-IV. The SF4 split-half reliability, test-retest stability coefficients and corrected SF4-FS correlations were good to excellent. The result of the Bland-Altman plot showed that the difference fell within 2SD was 95% and indicated a random error. The sensitivity, specificity positive predictive value (PPV), and negative predictive value (NPV) of the stepwise screening were good. There was an interaction (p < .001) between the IQ level (≥111) and gender on the accuracy of SF4, SF4 might get underestimated on females with the IQ level (≥111) than on males. In conclusion, SF4 is a valid and reliable instrument for use in the clinic, and its clinical application, stepwise screening and influencing factors in clinical use are discussed herein.

The fastclime Package for Linear Programming and Large-Scale Precision Matrix Estimation in R.

We develop an R package fastclime for solving a family of regularized linear programming (LP) problems. Our package efficiently implements the parametric simplex algorithm, which provides a scalable and sophisticated tool for solving large-scale linear programs. As an illustrative example, one use of our LP solver is to implement an important sparse precision matrix estimation method called CLIME (Constrained L1 Minimization Estimator). Compared with existing packages for this problem such as clime and flare, our package has three advantages: (1) it efficiently calculates the full piecewise-linear regularization path; (2) it provides an accurate dual certificate as stopping criterion; (3) it is completely coded in C and is highly portable. This package is designed to be useful to statisticians and machine learning researchers for solving a wide range of problems.